Whoever, owing allegiance to the United States, levies war against them or adheres to their enemies, giving them aid and comfort within the United States or elsewhere, is guilty of treason and shall suffer death, or shall be imprisoned not less than five years and fined under this title but not less than $10,000; and shall be incapable of holding any office under the United States.

See, the thing is, we have declared war on an ideology, not a nation. If we declared war on a nation, it would be easier. But since we have declared war on an ideology, it gets really, really murky. The United States does have the separation of church and state, and we also have freedom of religion. Gadahn has the right to be Islamic if he wants to; we can’t take that away from him. If he is helping al Qaeda in planning attacks on the United States, or US interests, then he is an enemy combatant. But treason?